efsa-opinion-chromium-food-drinking-water

4.2.2.1. Data collection on food (excluding drinking water)
Chromium in food and drinking water
Before applying any data quality criteria 27 138 analytical results on chromium were reported on food
(17 958 as unspecified chromium, 9176 as total chromium and four as chromium and derivatives). No
data on chromium speciation were reported.
Based on the evidence discussed in Section 4.1. the CONTAM Panel decided to assume that
chromium analytical data reported in food refer to Cr(III). However, certain foods are prepared with
water to be consumed (coffee, tea infusions, and dry infant and follow-on food), and an incomplete
reduction of the Cr(VI) present in this water into Cr(III) may happen if the foods are ingested
immediately after their preparation. In these cases, the occurrence data on Cr(III) reported for dry
foods were used to estimate the exposure to Cr(III) while the occurrence data on Cr(VI) reported for
different types of drinking water were used to estimate the exposure to Cr(VI).
Of the reported data, 64 results were not considered for dietary exposure assessment as they belonged
to the category ‘Grain as crops’, whose final use is unknown. Then, samples reporting neither LOD
nor LOQ values were excluded together with those reported as ‘suspect samples’ related to the
sampling strategy (939 and 337 samples, respectively). Finally, ten samples with exceptionally high
concentrations of chromium as compared with the rest of the samples in the same food category were
excluded (2-3 orders of magnitude higher). They were two samples of ‘Grains and grain-based
products’, one unspecified (12 100 g/kg) and one of ‘Wheat rolls, white’ (13 500 g/kg), and eight
samples of beer with reported values between 5100 and 9000 g/kg. The decision to exclude the eight
samples of beer was based on diverse pieces of evidence. The reported values were three orders of
magnitude higher than those reported for the rest of the samples in the food category ‘Beer and beerrelated
beverage’ (average value of this category = 8.3 g/kg, n = 493). This average value was similar
to those reported in the literature for the presence of chromium in beer, 0.48-56 g/kg (Anderson and
Bryden, 1983), 0.6-13.6 g/kg (Kovács et al., 2007) or 6-8 g/kg (Reczajska et al., 2005). Based on
this, and the fact that no plausible explanation for the high concentrations was found and the data
provider could not confirm these eight analytical results, it was decided to exclude the eight samples
of beer from the final dataset.
After these steps a total of 25 788 analytical results remained in the database.
Almost 50 % of the results were left-censored data and, therefore, special attention should be paid to
the LODs and LOQs reported. To avoid overestimation of the exposure calculations at the upper
bound (UB) and underestimation at the lower bound (LB) it was decided to establish a cut-off value
for the reported LOQs above which samples were excluded from the final dataset. In order to establish
an appropriate LOQ cut-off the distribution of the LOQs reported for the different foods at different
FoodEx levels was evaluated (FoodEx levels 1, 2 and 3). Those analytical results, within one specific
food category and at the selected FoodEx level, that reported LOQs above the 95 th percentile of the
LOQ distribution were excluded. In Table 5 are shown the different cut-offs selected for the different
food groups. It can be seen that in most of the cases the cut-off was applied at FoodEx level 1.
However, specific cut-offs were applied for some specific food groups at FoodEx level 2 and 3 when
needed (Table 5). In addition, an exception was made for the food category ‘Food for infants and
small children’. For this category, the LOQ cut-off selected was the 75 th percentile (50 g/kg) instead
of the 95 th percentile (1000 g/kg) as the samples with LOQ = 1000 g/kg were all left-censored data.
The exclusion of these data avoided the bias of the occurrence values in this food category since the
quantified values showed average chromium concentrations of 75 g/kg.
Following this approach a total of 1 159 analytical results were excluded (4.5 % of the total), among
them 226 corresponding to the food groups ‘Vegetable and vegetable products (including fungi)’ and
‘Starchy roots and tubers’. Among the excluded samples only 110 were quantified results.
EFSA Journal 2014;12(3):3595 37